Spark Streaming初试

yum install nc.x86_64

./bin/spark-shell --total-executor-cores 34

敲入下面程序：

import org.apache.spark.SparkConf

import org.apache.spark.streaming.{Seconds, StreamingContext}

import org.apache.spark.storage.StorageLevel

val ssc = new StreamingContext(sc, Seconds(1))

val lines = ssc.socketTextStream("hostname", 9999, StorageLevel.MEMORY_AND_DISK_SER)

val words = lines.flatMap(_.split(" "))

val wordCounts = words.map(x => (x, 1)).reduceByKey(_ + _)

wordCounts.print()

ssc.start()

ssc.awaitTermination()

在hostname机器，安装nc后，nc -lk 9999

不断输入字符，例如hello world，会在启动spark-shell的机器不断统计每次输入数据的字符频率统计。

参考

http://spark.apache.org/docs/latest/streaming-programming-guide.html

https://github.com/apache/spark/blob/master/examples/src/main/scala/org/apache/spark/examples/streaming/NetworkWordCount.scala